One more new layer should be created (Create new layer) on which we’ll use the Paint Bucket Tool (G) to picture it in white.

We’ll apply the next filter’s option – Filter>Noise>Add noise

The next parameters will be applied for the layer: Fill 18% on the layer
Blending mode-Darken Color

Find in Internet a picture representing a retro car, cut it out and place it the way it is demonstrated next image:

Apply the here demonstrated parameters for the photo’s layer.
Blending Options>Drop Shadow